1. Field of the Invention
This invention relates to an acoustic output device having ultradirectivity, as well as an electronic apparatus using this device. More particularly, the invention relates to an acoustic output device for realizing a man-machine interface by sound waves, as well as an electronic apparatus using the device.
2. Description of the Related Art
An electronic apparatus is known in which various indications and messages are provided as outputs not only by an indicator such as a display but also in the form of audio. However, when an electronic apparatus of this kind is used in an office or the like, the audio is an annoyance to those in the vicinity and therefore the operator is required to use a headphone or earphone.
When the headphone or earphone is used, however, the operator cannot hear other sounds, such as the ringing of a telephone. In addition, wearing a headphone at all times is bothersome and does not allow good operability.